Optoelectronic components on an organic basis, for example an organic light emitting diodes (OLED) or an organic solar cell, are being increasingly widely used.
An OLED may include for example two electrodes, for example two contact metallization designed as an anode and a cathode, with an organic functional layer system therebetween. The organic functional layer system may include one or a plurality of emitter layer/s in which electromagnetic radiation is generated, for example, one or a plurality of charge generating layer structure each composed of two or more charge generating layers (CGL) for charge generation, and one or a plurality of electron blocking layers, also designated as hole transport layer(s) (HTL), and one or a plurality of hole blocking layers, also designated as electron transport layer(s) (ETL), in order to direct the current flow.
At least one part of the organic functional layer system may include organic substances and/or organic substance mixtures. However, organic substances and/or organic substance mixtures can be susceptible to harmful environmental influences. A harmful environmental influence can be understood to mean all influences which can potentially lead to degradation or aging, for example a crosslinked state or crystallization, of organic substances and/or organic substance mixtures and can thus limit the operating period of the OLED, for example. A harmful environmental influence can be for example a substance harmful to organic substances or organic substance mixtures, for example oxygen and/or water.
For protection against harmful environmental influences, an OLED is customarily encapsulated. During the encapsulation of an OLED, by way of example, the organic functional layer structure and the electrodes are surrounded with an encapsulation layer that is impermeable to harmful environmental influences, for example a thin film that is impermeable to water and oxygen.
The encapsulation layer for thin-film-encapsulated organic light emitting diodes should be absolutely free of defects. In the course of encapsulation, however, the situation in which defects are still located in the encapsulation layer cannot be completely ruled out. Even a microscopic defect or a diffusion channel along a grain boundary in said encapsulation layer can lead to a defect of the entire OLED. As a result, non-luminous, circular points (black spot) can form in the field of view of the OLED by the action of moisture and can grow over the course of time.
In order that the potential damage for an OLED is kept small, in one conventional method a glass cover is laminated onto the encapsulation layer by a laminating adhesive. However, only the rate at which water diffuses into the OLED, for example, can be reduced by the glass cover. Water can for example still diffuse into the organic functional layer structure through the laminating adhesive, such that for example a defect in the encapsulation layer of an OLED is merely slowed down as it leads to a visible defect.
In another conventional method, a cavity glass can be adhesively bonded to the OLED, wherein the adhesive bonding is effected in the geometrical edge of the OLED and a water-absorbent material is set up in the cavity.
In another conventional method, a glass cover can be applied to the encapsulation layer for example by frit bonding (glass frit bonding/glass soldering/seal glass bonding) by a conventional glass solder in the geometrical edge regions.